1. Field of the Invention
The invention concerns a method for producing wheel pans for motor vehicle wheels.
2. Description of the Related Art
The production of wheel pans for motor vehicle wheels, i.e., the center web of a vehicle wheel, generally starts with sheet bars, which in turn are punched out or burned out of strip material or wide flat steel. This method of production generates a large amount of material scrap which can be as high as 35 to 40%.
To reduce this very large amount of material waste, various wheel manufacturers have tried to produce the wheel pans from cylindrical hoops. So far this has been successfully realized only with a very expensive 2-step orbital press-forming process.
In this production process, a cylindrical hoop is first produced, which is then shaped into a cup by orbital press forming. The bottom of the wheel pan is pre-shaped in a second orbital press-forming step. The wheel pan is then finished in the conventional way.
Since this process is mainly a material bulging process, very high forces are required and it can be realized only with very high capital expenditures.
DE Patent reference 493 472 describes another method, in which production begins with a flat bar, i.e., a rectangular strip, which is then tapered toward one edge and simultaneously rounded by rolling it between conical rolls. This results in the formation of an open circular ring, whose ends are then joined. The final shaping of the pan is then carried out in a pressing or drawing process.